1. Field of the Invention
This invention relates to pool safety equipment and more particularly relates to pool drain covers.
2. Description of the Related Art
The filtration of swimming pools, wading pools, and spas requires the use of powerful pumps that remove water through a drain or drains. These pumps create such a strong suction force that the Federal Government estimates that between 1997 and 2003, 150 deaths and serious injuries, including disembowelment, are attributable to pool drains. To prevent future deaths and injuries, several devices have been developed that cover pool drains in ways that mitigate the potential for suction entrapment, entanglement, or disembowelment.
Various grate and perforated plate designs have been employed to prevent swimmers from coming into direct contact with a pool drain. However, the possibility still remains that the back or chest of an individual may cover the entire grate or plate, resulting in suction entrapment. Additionally, an individual's hair, jewelry, limbs, or swimsuit may become entangled on the other side of such a perforated plate or grate. To address the issue of entanglement certain gates are provided with, as depicted in FIG. 1, vertically disposed channels 102 extending from the openings of the grate. These channels prevent entanglement by preventing the twisting of hair, jewelry, or clothing that has passed through the grate from different openings. However, the problem of suction entrapment remains unaddressed. Additionally, grates with such vertically disposed channels require a large cavity 104 in a pool floor above the pool drain to house the channel's extending from the grate.
Unfortunately, although extending vertically disposed channels 102 may help avoid entanglement, the vertically disposed channels 102 do not mitigate the problem of suction entrapment of a large body area, such as a back or a chest covering the grate. Additionally, the requirement for such a large cavity in a pool floor makes it difficult to retrofit pools without such large cavities 104 with a grate comprising vertically disposed channels.
Certain designs, therefore, incorporate horizontally disposed channels to mitigate entanglement. These horizontally disposed channels extend outward radially from a central location near the pool drain to distal openings situated within a drain cover that sits on the pool floor. Since the cover rests on the pool floor, no cavity around the pool drain is required and the covers can more easily be added to existing pools. Additionally, the length of the channels places the distal openings along the perimeter of the cover in a number of locations that cannot all be easily covered by a single human body, thereby creating an obstacle to suction entrapment.
However, the horizontally disposed channels exhibit certain design flaws that fail to harness the full potential of horizontally disposed tubes to avoid entanglement and suction entrapment. For example, certain designs disclose channels defined by the gaps between a few ribs that support a flat disk shaped cover resting on a pool floor. By defining the channels as the space between these ribs, a minimal number of channels result and the resulting channels have a wide opening on the distal end and a narrow outlet near the pool drain.
Although it may be difficult for the body of a single individual to block a few openings on a radially disposed disk, the clothes of the individual, such as a large T-shirt, and/or additional individuals may block the few openings provided, even when those openings are disposed on the perimeter of a disk shape. Furthermore, channels with a wide opening can take in large amounts of hair, clothing, equipment, and jewelry. The tapering can create turbulence and cross currents that can entangle the material that may lodge in a narrowed region of the channel or on the other side of the channel's outlet. Additionally, the larger amount of material that enters a channel, the larger amount of material that may make it to the outlet of the channel to entangle with material from other channels.
An additional design discloses curved channels that twist their way from the opening at the distal ends to outlets at the pool drain. Twisting channels result in internal turbulence that may promote entangled masses within a channel that may lodge in a turning passageway or beyond the outlet of the channel. Additionally, the curved path of hair, clothing, jewelry and other items sucked into such channels results in increased friction and opportunities for catching when efforts are made to extract these items. For example, a piece of jewelry, such as a cross that entered a tube along its length, may become entrapped by a cam action within the curved channel when pulled at an angle different from the angle at which the device entered the channel.